[jdk17u-dev] RFR: 8369226: GHA: Switch to MacOS 15

[Aleksey Shipilev]

Making GHA more stable.

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Commit messages:
 - Backport 1ea8cfa6dc8e6f96fd87553331abaae17ec173ea

Changes: https://git.openjdk.org/jdk17u-dev/pull/4115/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4115&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369226
  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4115.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4115/head:pull/4115

PR: https://git.openjdk.org/jdk17u-dev/pull/4115